Poisoning Effect of SO2 on Honeycomb Cordierite-Based Mn–Ce/Al2O3Catalysts for NO Reduction with NH3 at Low Temperature
Poisoning Effect of SO2 on Honeycomb Cordierite-Based Mn–Ce/Al2O3Catalysts for NO Reduction with NH3 at Low Temperature
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DOI：
10.3390/app8010095
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发表时间：
2018-01
期刊：
影响因子：
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通讯作者：
Chengzhi Wang;Zhang Cheng;Yonggang Zhao;Xinran Yan;Cao Peng
中科院分区：
文献类型：
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作者：
Chengzhi Wang;Zhang Cheng;Yonggang Zhao;Xinran Yan;Cao Peng
采用浸渍法制备了蜂窝状堇青石基Mn-Ce/Al 2 O3催化剂，并在自制的固定床管式反应器中对NH3、SO2和/或H2O以及无SO2和/或H2O存在下的NOx低温选择性催化还原（SCR）反应进行了研究。催化剂在100 °C下在不存在SO2的情况下达到近80%的NOx转化率。然而，在相同的条件下，SO2降低蜂窝堇青石基Mn-Ce/Al 2 O3催化剂的催化活性（80%至72%）。这一发现表明，该催化剂在低温下表现出高活性，并且在50 ppm SO2存在下表现出优异的抗SO2性。采用扫描电子显微镜（SEM）、能谱仪（EDS）、N2吸附-脱附、X射线衍射（XRD）、X射线光电子能谱（XPS）、热重-差热分析（TG-DTA）和傅里叶变换红外光谱（FT-IR）等方法对新鲜和硫酸化的蜂窝状堇青石基Mn-Ce/Al 2 O3催化剂进行了表征。表征结果表明，SO2的失活主要是由于SCR过程中硫酸氢铵和硫酸化CeO 2在催化剂表面沉积所致。生成的硫酸盐通过堵塞孔道和占据活性中心而抑制了催化剂的活性。此外，SO2和NH3之间的竞争吸附总是降低催化活性。
Honeycomb cordierite-based Mn–Ce/Al2O3 catalysts were prepared by the impregnation method and used for low-temperature selective catalytic reduction (SCR) of NOx with NH3, with and without SO2 and/or H2O in a homemade fixed-bed tubular reactor. The catalyst reached nearly 80% NOx conversion at 100 °C in the absence of SO2. However, SO2 reduces the catalytic activity (80% to 72%) of the honeycomb cordierite-based Mn–Ce/Al2O3 catalysts under identical conditions. This finding demonstrated that the catalyst exhibited high activity at low temperature and excellent SO2 resistance in the presence of 50 ppm SO2. The fresh and sulfated honeycomb cordierite-based Mn–Ce/Al2O3 catalysts were characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), N2 adsorption–desorption, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), thermogravimetry and differential thermal analysis (TG-DTA), and Fourier transform infrared (FT-IR) spectroscopy. Characterization results indicated that the deactivation by SO2 was primarily the result of the deposition of ammonium hydrogen sulfate and sulfated CeO2 on the catalyst surface during the SCR process. The formed sulfates depressed the catalytic activity via the blocking of pores and the occupation of active sites. Additionally, the competitive adsorption between SO2 and NH3 always decreased the catalytic activity.